Is it possible to replace existing nodes in an RKE2 environment? Say that I have 3 master nodes and 3 worker nodes based on Linux distro ‘A’, but we would want to switch to another distro ‘B’: could we, one by one of course, shut down master nodes and start RKE2 on a new node with the same IP address / DNS name? Would that integrate / synchronize as required or is that not the way it would work?
I think you’d have a harder time trying to keep hostname/IP the same. Probably easier to drain and remove your distro A masters one at a time and then join a distro B master then do the same for the workers. Remember that masters & etcd will be somewhat unstable with even nodes and they know how many they’ve had max for quorum, so that’s why I recommend removing one and then adding rather than adding and then removing (not sure but might be possible to accidentally get stuck thinking it should have five so three is minimum for quorum).
That’s just a guess, not something I’ve tried.
Ok, so generally that should work, except having the same node names and IP addresses,…well, I will give it a try then!
I think it can work with the same node names & IP addresses, but I’ve also heard about people having trouble with it taking a while before Rancher realizes a deleted node is gone, so that’s why I’d lean towards using different host/IP just to avoid that potential complication.
Same host/IP is a “should work” thing, but I’ve spent a lot of my work life hunting down the “should work” thing that happens not to in the particular instance.